你可能感興趣的試題

Which of the following SQL statements will return the year and average salary for all employees hired within a given year that have a salary greater than $30,000?（）

A.SELECT * FROM t1 UNION SELECT * FROM t2
B.SELECT * FROM t1 UNION DISTINCT SELECT * FROM t2
C.SELECT * FROM t1 INTERSECT SELECT * FROM t2
D.SELECT * FROM t1 WHERE (c1,c2)= (SELECT c1,c2 FROM t2)

單項(xiàng)選擇題

Given the following table definition:
STOCK: item VARCHAR(30) status CHAR(1) quantity INT price DEC(7,2)
If items are indicated to be out of stock by setting STATUS to NULL and QUANTITY and PRICE to zero, which of the following statements would be used to update the STOCK table to indicate that all the items whose description begins with the letter "S" are out of stock?（）

A.UPDATE stock SET (status = NULL; quantity, price = 0) WHERE item LIKE S%
B.UPDATE stock SET (status, quantity, price) = (NULL, 0, 0) WHERE item LIKE S%
C.UPDATE stock SET status = NULL, SET quantity = 0, SET price = 0 WHERE item LIKE 'S%'
D.UPDATE stock SET (status = NULL), (quantity = 0), (price = 0) WHERE item LIKE S%